Uphonor motorized zone controller life

I have a small system with four A3020522 Uphonor zone valves. Out of curiosity, if you have any experience with the things, how long do they last? The first set all ended up cracking their housings after a few years and were replaced. Over the years, I've replaced a couple more for various reasons, and just found one whose end switch is intermittent so I've ordered some new ones which should give me a few spares to have on hand. I expected them to need replacement on occasion, but they only seem to last 3-4 years or maybe a little longer.

What has been your experience?

We are an Uponor/Wirsbo "partner" service/installation company here in Minneapolis. The old unit can be a bother. We replace the zone valves if we must, but would rather convert them to the much more reliable thermal actuators. When replacing a the old Wirsbo zone valves we usually start with the valve, adapter ring and top off with the new actuator. This is especially true if they have leaked in the past. We also check for water quality as this can have a long lasting negative effect on many of the radiant floor heating system components.